Conventional laser printer toner cartridges are manufactured to a relatively high degree of precision necessary for proper operation and good printed image quality, with most tolerances measured in the thousandths of an inch. Of importance to the proper operation of a laser toner cartridge is the maintenance of alignment and orientation of its various components. Original equipment manufacturers (OEM) achieve the rigidity necessary to maintain the alignment and orientation of components, in substantial part, by ultrasonically welding the sections of the toner cartridge together. The process of repairing a spent toner cartridge typically requires that the cartridge be disassembled. Specifically, the toner hopper section of the cartridge, which holds the toner, is separated from the magnetic or developer roller section of the cartridge. When the separated hopper and roller sections are joined back together, precise alignment and orientation of performance critical components are necessary, particularly among the magnetic or developer roller section, the hopper port seals, and the joining of the magnetic or developer roller housing to the hopper tank section.
Conventional cutting of the toner cartridge is accomplished with mechanical saws or grinders to separate the magnetic or developer roller section from the toner hopper section. Conventional toner cartridge separation methods and devices are described in, for example, U.S. Pat. Nos. 5,223,068; 5,407,518; 5,525,183; and, 5,676,794. Typically, conventional techniques use a circular saw blade having a thickness in the range of about 0.020 inch to about 1/16th of an inch to cut or separate the developer roller section from the toner hopper section of the cartridge. These conventional cutting processes create a problem for re-assembly due to loss of a significant amount of the plastic material that formed the cartridge. This loss of material changes the cartridge and its components dimensionally from the OEM design specifications, and makes difficult the re-assembly of the cartridge with proper orientation and alignment. Separating the cartridge in this conventional way causes a loss of material that must be replaced when re-assembling the cartridge as it is rebuilt. Because of this loss of material, a shim is typically used. The shims are also referred to as spacers or stepped gaskets, and use of such components carries with it a significant risk that the repaired toner cartridge will not be returned to the OEM original design specifications.
A problem has existed in aligning the hopper tank seal, toner hopper and magnetic or developer roller housing when reassembling the three components with enough precision necessary to achieve a cartridge to match the OEM specifications. The conventional approach to this problem has been to manually align and fit the two sections together, with or without the aid of a positioning jig, then to manually secure the sections together with a number of metal clips. The sections maybe fastened together with clips, adhesive or glue in the reassembled cartridge. This technique, while generally effective, suffers many other deficiencies, or drawbacks. The most common drawback is that the dimensional height of the magnetic or developer roller housing has now been changed when measured to the OEM specifications for the toner hopper port to the magnetic or developer roller housing. Another drawback is that both metal clips and adhesives are consumables, which increases production costs and the cost of the final product. Another significant drawback is that manual reassembly is quite labor intensive, and is subject to human error and thus to a variation in quality. In the case of reassembly with adhesives or glue, there typically is a period of a few to several minutes for bonding to take place, during which alignment must be maintained and which often fuses or bonds the sections together, rendering subsequent additional remanufacturing or repair cycles difficult or impossible. An additional drawback from sawing is the use of metal clips to reassemble the cartridge in that the rigidity imparted by the saw cut is difficult to achieve, and over the working life of the cartridge the clips may loosen or become disengaged entirely. In such event, as a result of a loss of proper alignment of the toner hopper tank, seal and the magnetic or developer roller housing, excessive toner may accumulate on the magnetic or developer roller with the result of transferring too much toner to the photoconductive printing drum (OPC) and then to the printer paper, thereby degrading the printed page giving unsatisfactory image results and quality. Further, disengagement of one of the metal clips may permit toner to leak from the cartridge. In many printing devices, such as printers, facsimile, machines or copiers, the path of the paper through the printing device passes nearby to an edge of the toner cartridge where the metal clips have been installed. Paper jams can occur if a loose metal clip projects into the paper path. Printer failure can occur if a cartridge clip falls into the printer from a toner cartridge that has poorly cut pieces when assembled with clips.
OEM laser toner cartridges typically are sealed by ultrasonic welding. For the best quality, a remanufactured toner cartridge should be rebuilt to the same OEM specifications as designed. Disassembling the toner cartridge and reassembling it without losing its original design features, gives the best results. That technique has, until now, been unavailable for use in the remanufacture or reassembly of toner cartridge Industry. A primary impediment to the use of separating, or splitting the magnetic or developer roller from the toner hopper is lack of precision in the separation process, and loss of plastic material that formed the original cartridge. The less material lost during the cartridge component separation process, the better is the result of the reassembly process in joining the hopper section to the roller section of the cartridge in order to maintain the original integrity and dimensionality of the cartridge.
Hence, upon separation of the hopper and roller sections, if the cartridge is split at the weld joint without destroying anything else at that point, then the cartridge can be reassembled as close to the original equipment manufactures specification as possible.